How To Insulate Under An Existing Concrete Floor

Where concrete floor slabs have replaced earlier floors they may include a damp proof membrane dpm but unless laid comparatively recently they might not be well insulated.

How to insulate under an existing concrete floor.

Typically the insulation would be situated below the slab and below the damp proof membrane for heavy duty use whilst normal domestic buildings would have a higher performing lower compressive strength material. Place it into the space between your existing floor joists relying on friction to hold it in place. Most modern homes have a solid floor for example. Check out this article for a list of slab edge insulation solutions and episode 125 for my interview with henry edney of maxraft.

The first thing to consider when looking into different types of concrete floors is why it s so important to insulate the floor slab. Insulating a solid floor. This allows an area for insulation and fill material under the slab. Insulating a concrete floor alternative options.

Up to 80 of heat loss in a floor slab occurs around the edges. But it isn t cheap and it can cause additional problems such as raising the floor level too much. Step 1 excavate the area under the slab to 12 inches below the planned level of the top of the slab. There will be a damp proof membrane under the insulation and possibly a second membrane on top depending on the type of screed.

Dealing with the edges the foam insulation and two layers of plywood can add as much as 2 inches of height to the garage floor. Insofast is a diyers dream a simple way to install insulation needing only a hand saw utility knife and caulking gun. Insulating a concrete floor can save you money on your heating bill making an attached garage or basement warmer and by extension the rest of your house. Add wire insulation hangers as needed to ensure a more secure hold.

The method shown above is the best way to insulate a concrete floor without digging it up and laying it again with insulation added below the finished surface. Insofast s insulation panels provide an easy way to insulate a cold concrete floor. In addition to offering insulation and energy savings the plywood subfloor described here can provide the perfect foundation for finish flooring such as carpeting adding warmth in look as well as in feel. Insulation is laid on the concrete and covered with a screed.

Where floors do include a dpm and show no evidence of moisture laying a floating wooden floor or thermal underlay with a carpet on top is often the easiest means of improving their thermal performance. But when adding insulation to an existing slab the vapor barrier is laid over the top of the slab before the foam insulating panels are installed. If your concrete floor is for industrial or heavy duty applications then any insulation you use needs to have a high compressive strength to take the weight of whatever is above.